Bimetallic filament positioning device



1965 w. E. GLENN, JR

BIMETALLIC FILAMENT POSITIONING DEVICE Filed Oct. 19, 1962 in van tor-a-I/V/V/Ia m E. 6/2 rm we,

/ Attorney United States Patent 3,213,318 BIMETALLIC FlLAMENTPOSITIONING DEVICE William E. Glenn, Jr., Scotia, N.Y., assignor toGeneral Electric Company, a corporation of New York Filed Oct. 19, 1962,Ser. No. 231,637 3 Claims. (Cl. 31594) This invention relates to anelectrical element positioning device and particularly to anelectrically controlled filament centering device for electron dischargedevices and the like.

It is frequently desirable to physically alter the position of afilament or other electrode inside an electron discharge device fromoutside the device. For example, in cathode ray tubes employing smallhairpin filaments for generating extremely small diameter electronbeams, it is frequently necessary to provide mechanical adjustmentexternally operated in order to adjust the centering of the emitting endof the filament. While the results of mechanical adjustment linkages ofthis type are satisfactory, the mechanism involved is expensive andcumbersome and moreover does not lend itself to automatic or remotecontrol centering.

It is therefore an object of the present invention to 'provide a simpleand economical means for centering and positioning filaments or otherelectrodes electrically or from a point remote from the electrode.

Briefly stated in accordance with an aspect of the present invention,the filament or electrode device is physically supported by means ofcurvilinear bimetallic means which carry current to the electrode. Byadjusting the current flow through the bimetallic means, its temperaturemay be altered and therefore its physical configuration.

In accordance with one embodiment of the present in- .vention, anelectron discharge device filament including two support leads isfurther supported by two pairs of curvilinear bimetallic members,disposed substantially orthogonally to one another. A first pair carriesthe filament current to one of the. filament support leads while anotherpair carries the filament current to the second filament support lead.The proportion of the filament current carried by each bimetallic memberof a pair is remotely adjustable with a potentiometer so a temperaturedifferential exists between the bimetallic strips connected to one ofthe support leads. The bimetallic member carrying a larger current tendsto distort the most and acts to cause movement of the filament in apredetermined direction.

The subject matter which I regard as my invention is particularlypointed out and distinctly claimed in the concluding portion of thisspecification. The invention, however, both as to organization andmethod of operation, together with further objects and advantagesthereof, may best be understood by reference to the followingdescription taken in connection with the accompany drawings wherein likereference characters refer to like elements and in which:

FIG. 1 is a perspective view of an embodiment of the present invention,and

FIG. 2 is a plan view of an embodiment of the present invention furtherincluding circuitry for its operation.

Referring to the drawing, a filament or element to be positioned orcentered, 1, is provided with two support conductors 2 and 3 which areparallel to one another and held in spaced relation by brace members 4and 5. Support member 2 is joined to two curvilinear currenttemperaturesensitive or bimetallic members 6 and 7 positioned approximately in linewith support conductors 2 and 3. These bimetallic members 6 and 7 areconveniently formed of a strip of steel at their outside radius rivetedor otherwise joined to a strip of brass or copper at their insideradius. The bimetallic members are attached 3,213,318 Patented Oct. 19,1965 ice to conducting posts 8 and 9, arranged substantially in linewith the support conductors 2 and 3 on either side of the filament andextended through an insulating base 10 to provide externally accessibleterminals.

A second pair of curvilinear current-temperature sensitive or bimetallicmembers 11 and 12 are joined to the support conductor 3, this supportconductor being foreshortened to allow bimetallic members 11 and 12 tobe attached thereto while passing over bimetallic member 7. Bimetallicmembers 11 and 12 are joined respectively to conducting posts 13 and 14,also embedded in common insulating base 10 on either side of thefilament. Conducting posts 13 and 14 as well as bimetallic members 11and 12 in general form a configuration substantially orthogonal to thatof bimetallic members 6 and 7 and their respective conducting posts 8and 9.

Member 10 is part of an envelope of an electron discharge type device,for example, of the cathode-ray beam type, wherein it is desirable toposition the electron beam 19 produced by filament 1 and acceleratedthrough an apertured focusing electrode indicated at 20. Filament 1 iscentered with respect to electrode aperture.

In order to control electrically the position of filament 1, the currentis varied through the bimetallic members. Referring particularly to FIG.2, a first potentiometer 15 is coupled between conducting posts 8 and 9and is provided with a slidable contact 16 operable to control thefilament movement. Similarly, the potentiometer 17 having slidablecontact 18 is disposed between conducting posts 13 and 14. Slidablecontacts 16 and 18 are conveniently coupled to a source of filamentpower 19.

In operation the device according to the present invention, provides forthe remote electrical centering or positioning of the filamentelectrodes. Positioning of slidable contacts 16 and 18 on potentiometers15 and 17 act to adjust the proportion of filament current flowing inthe bimetallic members which current acts to energize the filament 1 toan electron emitting tempera- The slidable contact 16 when moved towardsthe a larger proportion of the filament current to flow throughbimetallic member 7 than bimetallic member 6. Under such circumstances,bimetallic member 7 becomes heated and becomes more heated thanbimetallic member 6; since the brass strip is on the outside radius ofthe bimetallic member, the bimetallic member 7 will bend or curl morethan bimetallic member 6. Member 6, carrying less current, bends less.This causes support conductor 2 to move generally in the direction X inFIG. 2, that is towards conducting post 9, the same direction in whichslidable contact 16 was moved. Likewise movement of slidable contact 16in direction W will cause support conductor 2 to move in direction W,designated in FIG. 2.

Similarly movement of slidable contact 18 of potentiometer 17 in thedirection Y will cause movement of support conductor 3 in the Ydirection, and movement of slidable contact 18 in the direction W causesmovement of support conductor 3 in the direction W. Of course, since thefilament together with its support conductors and brace members is aunitary device, movement of one of the support conductors will have thesame directional effect upon the positioning of the filament electrode.For example, movement of support conductor 2 in the direction X bymovement of slide contact 16 in that direction will move the wholefilament assembly in that direction and will also cause movement ofbimetallic members 11 and 12 in the same direction. Since this is in adirection substantially orthogonal to the general configuration ofbimetallic members 11 and 12, no undue strain is imparted to members 11and 12. Also movement of the electrode structure in a Y direction has alimited mechanical effect upon bimetallic members 6 and 7. The electrodestructure tends to turn or hinge at support conductor 2.

While illustrated primarily with respect to the physical positioning ofa filament electrode, it is apparent the present invention in itsbroader aspects is applicable to other electrode elements and the liketo provide effective remote positioning thereof electrically, and, forexample, from outside the evacuated electron discharge device.

While I have shown and described several embodiments of my invention, itwill be apparent to those skilled in the art that many changes andmodifications may be made without departing from my invention in itsbroader aspects; and I therefore intend the appended claims to cover allsuch changes and modifications as fall within the true spirit and scopeof my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In an electron discharge device, an apparatus for positioning thefilament thereof comprising first and second terminals for saidfilament, a first pair of posts electrically conductive disposed oneither side of said filament, a pair of curvilinear bimetallic stripsextending one from each of said first pair of posts and joined in commonto the first terminal of said filament to mechanically support saidfirst terminal while carrying current thereto, a second pair ofelectrically conductive posts disposed in a line substantiallyperpendicular to a line between said first pair of posts, a second pairof curvilinear bimetallic elements extending one from each of saidsecond pair of posts and joined to the second terminal of said filamentto support said second terminal while carrying current thereto, andmeans supplying a proportionately variable current through said posts tosaid bimetallic elements to heat said elements while at the same timeenergizing said filament.

2. In an electron discharge device, an apparatus for centering thefilament thereof comprising first and second terminals for saidfilament, a first pair of conductive posts disposed on either side ofsaid filament, a pair of curvilinear bimetallic strips extending onefrom each of said first pair of posts and joined in common to the firstterminal of said filament to mechanically support said first terminaland carry current thereto, a second pair of conductive posts alsodisposed on either side of said filament and between said first pair ofposts in a line substantially perpendicular to a line between said firstpair of posts, a second pair of curvilinear bimetallic elementsextending one from each of said second pair of posts and joined to thesecond terminal of said filament to support said filament and carrycurrent thereto, a first potentiometer means connected between saidfirst pair of posts and including a first adjustable tap, a secondpotentiometer means extending between said second pair of posts andincluding a second adjustable tap, and means providing a current betweensaid first and second adjustable taps flowing proportionately throughsaid potentiometers and through said posts to energize said filament.

3. In an electron discharge device a filament centering devicecomprising a pair of support conductors for said filament with bracingmeans therebetween, a first pair of electrically conducting postssubstantially in line with and parallel to said supporting conductorsone on either side of said filament, a first pair of bimetallic memberseach joined at one end thereof to one of said first conducting posts andin common to one of said support conductors for supporting said filamentwhile supplying current thereto, a second pair of conducting posts oneon either side of said filament in a line substantially orthogonal to aplane containing said support conductors, a second pair of bimetallicmembers each joined at one end thereof to said second conducting postsand in common to the second support conductor for supporting saidfilament while supplying current thereto, and means supplying a varyingcurrent through said posts to said bimetallic members to adjust thefilament in position while energizing said filament.

References Cited by the Examiner UNITED STATES PATENTS 2,782,682 2/57Browning et al.

2,840,743 6/58 Marton et al 31315l 2,880,333 3/59 Dranetz 3108.5 X3,146,367 8/64 McNaney 313-86 GEORGE N. WESTBY, Primary Examiner.

1. IN AN ELECTRON DISCHARGE DEVICE, AN APPARATUS FOR POSITIONING THEFILAMENT THEREOF COMPRISING FIRST AND SECOND TERMINALS FOR SAIDFILAMENT, A FIRST PAIR OF POSTS ELECTRICALLY CONDUCTIVE DISPOSED ONEITHER SIDE OF SAID FILAMENT, A PAIR OF CURVILINEAR BIMETALLIC STRIPSEXTENDING ONE FROM EACH OF SAID FIRST PAIR OF POSTS AND JOINED IN COMMONTO THE FIRST TERMINAL OF SAID FILAMENT TO MECHANICALLY SUPPORT SAIDFIRST TERMINAL WHILE CARRYING CURRENT THERETO, A SECOND PAIR OFELECTRICALLY CONDUCTIVE POSTS DISPOSED IN A LINE SUBSTANTIALLYPERPENDICULAR TO A LINE BETWEEN SAID FIRST PAIR OF POSTS, A SECOND PAIROF CURVILINEAR BIMETALLIC ELEMENTS EXTENDING ONE FROM EACH OF SAIDSECOND PAIR OF POSTS AND JOINED TO THE SECOND TERMINAL OF SAID FILAMENTTO SUPPORT SAID SECOND TERMINAL WHILE CARRYING CURRENT THERETO, ANDMEANS SUPPLYING A PROPORTIONATELY VARIABLE CURRENT THROUGH SAID POSTS TOSAID BIMETALLIC ELEMENTS TO HEAT SAID ELEMENTS WHILE AT THE SAME TIMEENERGIZING SAID FILAMENT.